Method and device for determining meat tenderness

ABSTRACT

The invention concerns a method for determining the quality of meat, in particular beef, on the transformation site, comprising the following steps: a) collecting, on the transformation site, data on parameters pertaining to the group consisting of the animal&#39;s race, age, and category, and biological and/or physico-chemical parameters of the animal&#39;s carcass pertaining to the group consisting of weight, conformation, fleshing, the carcass pH and color, and the thickness of the hide; b) obtaining at least an optical spectrum of the meat at wavelengths pertaining to a spectral range from the visible to near-infrared; c) combining data obtained from steps a) and b), to determine the meat tenderness according to a predetermined law established with respect to a predetermined tenderness reference scale.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of International application No.PCT/FR99/01404, dated Jun. 14, 1999, which in turn claims priority ofFrench application No. 98/08536, filed Jul. 3, 1998.

The present invention relates to the determining of the tenderness ofmeat, in particular of beef, on the transformation site by means ofbiological and/or physico-chemical data and optical measurements in thevisible and near infrared range.

Among the numerous factors of quality of meat, such as juiciness,tenderness, colour, or flavour, tenderness is considered as the factorof quality which gives the most satisfaction to the consumer.

It is therefore economically important for meat producers to be able todetermine the tenderness of a meat rapidly and as early as possible inthe process of transforming the meat in the industrial environment(abattoir). Moreover, and above all, this determination must be reliablein order to guarantee the quality up to the stage of consumption.

A large number of industrial methods of determining the quality of meatare already known, in particular of the non-destructive type (i.e.without cutting away samples).

In the French Patent 1 550 169, a probe determines the colours of meatby means of a light transmitted by a piece of meat subjected toobservation. The instrument comprises an emission branch and a receptionbranch intended to be inserted into the meat. A lamp gives out a lightby the emission branch located opposite the reception branch. Such adocument does not specify the wavelengths of the light used. Moreover,only the colours of the meat are determined, which is insufficient inorder to determine the tenderness of the meat with a satisfactory degreeof reliability.

In the publication EP-A-0402877, a probe is inserted into a piece ofmeat in order to determine its quality. The technique used is to measurethe intensity of light reflected (reflectance) in the visible or nearinfrared spectrum. With such a probe it is only possible to estimate theconcentrations of one or more components of the meat, which is notsufficient to determine the tenderness of the meat with a satisfactorydegree of reliability.

The object of the present invention is to improve the reliability of theprior techniques for determining the quality and in particular todetermine the tenderness on the transformation site.

The invention relates to a method of determining the quality of meat, inparticular beef, which can be used on a production line on thetransformation site.

According to a general definition of the invention, the method comprisesthe following stages:

a) to collect, on the transformation site, data relating to parametersbelonging to the group formed by the breed, age and category of animalas well as biological and/or physico-chemical parameters of the animalcarcass belonging to the group formed by the weight, conformation,fleshing, the pH value and the colour of the carcass, as well as thethickness of the hide,

b) to obtain at least one optical spectrum of the meat corresponding towavelengths belonging to a spectral field ranging from visible light tonear infrared, and

c) to combine the data obtained at stages a) and b) with a view todetermining the tenderness of the meat according to a predeterminedequation drawn up relative to a predetermined scale of reference oftenderness.

The Applicants have observed that certain parameters of the animal andits carcass, such as breed, age and type of animal as well as weight,conformation, fleshing, the pH value, the colour of the carcass and thethickness of the hide etc. are data which are correlated withtenderness.

However, until now no model for determining tenderness has used thesedata directly, probably due to ignorance or a lack of interest thereinon the part of scientists.

In spite of this prejudice, the Applicants use them in order to combinethem furthermore with optical measurements with a view to a morereliable determination of the tenderness of meat on the transformationsite.

The data (breed, age, category of animal, weight, conformation,fleshing, pH value, carcass colour, thickness of hide etc.) arehereinafter referred to as “expert data”, because they derive from anin-depth knowledge of the animal and the features which influencetenderness.

The method according to the invention makes it possible to supply anobjective, nondestructive determination of the tenderness of meat whichcan be carried out on a production line on the transformation site in anindustrial environment without having recourse to sophisticated,expensive devices.

Moreover, the results of determination according to the invention aresufficiently reliable to be able to guarantee tenderness with a highlevel of probability at the time when the meat leaves the transformationsite in an industrial environment.

In practice, the stage b) is effected in reflection and/or emissionmode.

In transmission mode, stage b) comprises the following stages:

b 1) to provide a probe comprising an emission branch and a receptionbranch, spaced apart by a predetermined distance;

b 2) to insert the emission and reception branches into a selected pieceof meat to a selected depth;

b 3) to illuminate the piece of meat by means of the emission branchthus inserted into the piece of meat by wide-band light radiation at afrequency ranging from visible light to near infrared;

b 4) to receive the light transmitted by the piece of meat by means ofthe receiving branch thus inserted into the piece of meat; and

b 5) to record a transmission spectrum of the piece of meat ranging fromvisible light to at least near infrared.

In reflection mode, the probe comprises a single branch for emission andreception of the incident light and reflected light respectively.

In practice, the determination equation is drawn up over a significantseries of different pieces of meat of different animals for each ofwhich spectral data and non-spectral data are obtained according tostages a) and b) and compared to a scale of reference drawn up by meansof sensorial data and/or data of the shearing force, and/or of the forceof compression measured over the significant series of different piecesof meat.

Preferably, determination is carried out by a multidimensionalstatistical method such as the method of smallest partial squares, inorder to obtain a mathematical determination model intended to be usedon each piece of meat whose tenderness is to be determined.

According to another feature of the method, stage b) is effected on thecarcass, quarters, muscles or steaks.

A further object of the present invention is a device for determiningthe quality of meat, in particular beef, on the transformation site.

According to a general definition of the device according to theinvention, the device comprises:

means of collecting on the transformation site data relating toparameters belonging to the group formed by the breed, age and categoryof animal as well as biological and/or physicochemical parameters of theanimal carcass belonging to the group formed by the weight,conformation, fleshing, the pH value and the colour of the carcass, aswell as the thickness of the hide,

means of obtaining at least one optical spectrum of the meatcorresponding to wavelengths belonging to a spectral field ranging fromvisible light to near infrared, and

processing means for combining the data obtained at stages a) and b)with a view to determining the tenderness of the meat according to apredetermined equation relative to a predetermined scale of reference oftenderness.

Further features and advantages of the invention will appear from thedetailed description below and from the attached drawings, in which:

FIG. 1 shows diagrammatically a continuous production line of anindustrial abattoir on which the invention is set up;

FIG. 2 shows spectra from absorption to reflection obtained on cows ofdifferent tenderness according to the invention;

FIG. 3 shows diagrammatically the essential constituent means of adevice for obtaining a transmission spectrum according to the invention;

FIG. 4 is a section view showing a transmission probe according to theinvention; and

FIG. 5 is a section view showing the constituent means of a reflectionprobe according to the invention.

The drawings comprise in essence elements of a certain character. Tothis end, they may not only help to explain the detailed descriptionbelow, but also contribute, if necessary, to the definition of theinvention.

The present invention is intended more particularly to be put intoeffect on a meat transformation site (slaughter and cutting up), e.g. onthe continuous production line of an industrial abattoir.

It is applied to any type of meat, in particular originating from cows,sheep, goats, pigs or the like.

In general, a slaughter and cutting site comprises a reception bay forlive animals, a slaughter bay, bays for preparation of the slaughteredanimals to form carcasses, bays for cutting at least intodemi-carcasses, a phase of bleeding, and if necessary bays for cuttingand preparation into quarters, muscles or steaks.

Certain features or parameters of the animal and its carcass are knownor easily measurable on the transformation site.

For example, the breed RA (Charolais, Limousine etc.), age AG, categoryCA (young cow, ox, cow, heifer etc.) of animal are gathered at the bayfor receiving the live animal. These data, together with the origin ofthe animal NE, are available on the animal's identity card.

With reference to FIG. 1, biological and/or physico-chemical features orparameters of the animal are measured on the transformation site, inparticular on the continuous production line 1 of an industrialabattoir.

Among these features is found the weight PD of the carcass, which ismeasured by means of a weighing scale 5 placed on the aerial conveyor 3of the continuous production line 1, e.g. before the bleeding bay.

The conformation CO of the carcass CC is also evaluated. Five levels ofconformation CO are provided in accordance with the EUROP classificationgrid, whose criteria are in particular described in regulation no.1208/81 of the Council of European Communities of Apr. 28, 1981, whichlays down the community classification grid for beef carcasses as wellas in regulation no. 1026/91 of the Council of European Communities ofApr. 22, 1991.

The fleshing EE of the carcass CC is also evaluated. Five levels varybetween “very poor” and “very good”. In practice, the fleshing EE isevaluated before the bleeding bay according to criteria described inparticular in regulation no. 1208/81 of the Council of EuropeanCommunities of Apr. 28, 1981 mentioned above.

The colour CL of the carcass CC is likewise measured, e.g. before thebleeding bay. Measurement of the colour CL may be obtained by acolorimeter 7. An expert may also measure the colour CL of the carcassCC with the naked eye.

The pH value (degree of acidity) of the carcass CC may also be measuredby means of an instrument for measuring acidity (not shown) at varioustimes after slaughter, e.g. 1, 2, 3, 8, 12 or 24 hours after slaughter.For example, the pH value of the carcass is measured according to theFrench standard NF V 46-001 of December 1996 entitled “Viandes de grosbovins-conditions de valorisation du potentiel de tendrete” (Meat fromfull-grown beef cattle-conditions for evaluating the potential fortenderness).

Another relevant indicator for determining tenderness, as will be seenin more detail below, is the thickness of the hide EC, which may bemeasured after slaughter by means of weighing the hide combined with, ornot, measurement of the surface area thereof.

All these data DAC, known as expert data, are recorded and stored in acomputer memory 11 connected to a printer and a monitor 13.

The Applicants have observed that it may be advantageous to integratethese expert data DAC into a model for determining tenderness.

Moreover, the results of determination are further improved when theseexpert data DAC are combined with optical spectral data DSP relating tothe reflection and/or emission of the meat within the visible and nearinfrared range.

It should be noted that in the presence of animals having substantiallythe same biological and/or physico-chemical characteristics DAC,determination of tenderness may be effected, with a relativelysatisfactory degree of reliability, only on the basis of opticalmeasurements ranging from visible light to near infrared.

Furthermore, in the case of animals having different biological and/orphysico-chemical characteristics, the number of biological and/orphysico-chemical characteristics to be combined depends on the degree ofreliability of determination of tenderness to be reached.

Thus, the degree of reliability of determination which integratesnumerous DAC parameters will be better than that of a determinationwhich only integrates a few DAC parameters.

The spectral measurements DSP may be obtained on the transformation sitebefore, during or after bleeding, and on carcass, quarters, muscles orsteaks by means of a suitable apparatus 15.

The computer 11 is capable of determining the tenderness of the piece ofmeat thus observed according to a predetermined equation ofdetermination of tenderness in order to attach or print the level oftenderness of the piece of meat on a suitable band 13.

In practice, the equation for determination is drawn up over asignificant series of different pieces of meat (sirloin, topside etc.)of different animals (cows, young beef cattle, etc.) for each of whichspectral data DSP and non-spectral data DAC are obtained and compared toa selected scale of reference 19.

The spectral data DSP are obtained by means of at least one opticalmeasurement of the light transmitted and/or reflected by the piece ofmeat in transmission and/or reflection mode, which will be described inmore detail with an example. The optical measurement is advantageouslycarried out in the range of 400-2500 nm, if necessary restricted to400-2100 nn.

The spectral data DSP of various pieces of meat from different animalsare stored in a memory 21 in association with the non-spectral data DACof each animal. All these data DAC and DSP are managed in a database 17.

For each cow (or other animal), data DAC are available from the database17. The spectral data DSP and non-spectral data DAC thus obtained arecompared to a selected scale of reference 19.

For example, the scale of reference 19 is drawn up by means of sensorialdata and/or data of shearing force and/or compression force obtained oneach piece of meat of each animal taking part in drawing up the equationof determination.

The reference data of tenderness 19 are stored in the database 17connected to the computer 11.

The shearing forces are established for example according to a method ofthe WARNER BRATZLER type, defined by WHEELER, KOOHMARAIE, CUNDIF andDIKE in 1994 in their study entitled “Effects of cooking and shearingmethodology on variation in Warner Bratzler shear force values in beef”,which appeared in the periodical “Journal of Animal Science”, no. 72,1994.

As a variant, the compression force is established on slices of steakboiled according to the VOLODKEWICH method.

The scale of reference 19 may be evaluated also by means of a tastingjury, as is described in “Research Guidelines for Cookery, SensoryEvaluation and Instrumental Tenderness Measurements of Fresh Meat”,published by the American Meat Science Association, 1995 edition.

In the case of sirloins of beef, the tenderness of each of these isevaluated for example by a measurement of the shearing force accordingto the Warner Bratzler method mentioned above.

An analysis is then carried out on each optical spectrum according to aselected statistical processing method 12, e.g. an “analysis of maincomponents known as AMC”. This AMC makes it possible for example toisolate the first 10 main components which will form the spectralvariables DSP of the spectral model according to the invention.

In practice, each parameter (spectral data DSP or expert data DAC) isconsidered an individual variable used in a mathematical model 12 (e.g.multiple regression) in order to determine tenderness.

The equation or model of determination may be of the type:

Determination of tenderness=C+a ₁ X ₁ +a ₂ X ₂ + . . . +a _(n) X _(n)

where

C is a constant

a₁ to a_(n) are coefficients, and

X₁ to X_(n) are the spectral variables DSP and non-spectral variablesDAC.

An experiment was carried out on 100 sirloins of beef The mathematicalmodel, taking into account the entire spectrum from 400 to 2500 nm inreflection mode and the data DAC, makes it possible to determinetenderness with a coefficient of multiple correlation R² of 0.62.

More reliable models of determination were established onsub-populations of this sample. For example, for the 25 cows of thebreeds Charolais, Limousine or a cross the determination of tendernessis associated with a coefficient of correlation R² of 0.95. Thiscoefficient operates, in order of importance for the non-spectralvariables DAC, the following parameters:

colour of the sirloin CL,

thickness of hide EC,

weight of carcass PD,

conformation CO,

pH value during bleeding,

age of animal AG.

For the spectral data, the main components 3, 7, 11, 5, 10 and 2 are themost significant. They comprise the wavelengths generally used fordetecting proteins, fat, water content, collagen, as well as the pigmentof the meat. For example, these are the following wavelengths: 460, 660,800, 880, 980, 1020, 1120, 1320, 1580, and 1920 nm.

Each of these parameters is correlated significantly with tenderness.However, taken alone, they do not guarantee tenderness with greatprobability. Thus, for example the colour of the sirloin is correlatedwith tenderness with a coefficient of correlation R² of 0.65, whereasthe thickness of the hide is correlated with tenderness with acoefficient of 0.43.

In another example of the invention, the Applicants demonstrated thatthe spectral data DSP in emission mode make it possible to obtain a gooddetermination of tenderness (R² of 0.6) on the topsides of 100 youngcattle. This coefficient is improved by integrating certain expert dataDAC. For example, a coefficient of correlation of 0.95 was obtained fortopsides (semitendinosus) of 24 young cattle of milk-producing breed.

This coefficient brings into play, in order of importance fornon-spectral variables, the following parameters:

pH value during bleeding,

colour of the carcass CL,

fleshing EE,

thickness of hide EC,

weight of carcass PD,

age of animal AG.

In this example in transmission mode, certain preponderant wavelengthscorrespond to wavelengths generally used for determining the pigment ofthe meat (560 nm), fat (930 and 1215 nm) and water content (1682 nm).

With reference to FIG. 2, various absorption spectra are shown ofsirloins of tough and tender cows from the visible (400 nm) to nearinfrared (2480 nm) in reflection mode.

It will be seen that certain peaks of absorption are strongly correlatedwith tenderness. It should be noted that it is desirable in terms ofreliability to measure a full optical spectrum at least from 400 to 2100nm.

The spectrum DSP1 is that of a sirloin of a cow whose tenderness isevaluated at 6.10 on the WARNER BRATZLER-type scale of reference, i.e. atough sirloin.

The spectrum DSP2 is that of a sirloin of a cow whose tenderness isevaluated at 6.90 on the WARNER BRATZLER-type scale of reference, i.e. atough sirloin.

The spectrum DSP3 is that of a sirloin of a cow whose tenderness isevaluated at 2.9 on the WARNER BRATZLER-type scale of reference, i.e. atender sirloin.

The spectrum DSP4 is that of a sirloin of a cow whose tenderness isevaluated at 3.30 on the WARNER BRATZLER-type scale of reference, i.e. atender sirloin.

With reference to FIGS. 3 and 4, a device has been described forobtaining spectral data, operating in transmission mode.

The device for obtaining spectral data 15 comprises for example agun-type pricking device 20 comprising a housing 22 and a probe 23 withtwo branches 23A and 23B, one 23A being dedicated for emission and theother 23B for reception. The branches 23A and 23B of the probe areintended to be inserted into a selected piece of meat to a selecteddepth. The branches 23A and 23B are parallel to one another and spacedapart at a predetermined distance. The two branches are connectedtogether by a base 24 forming a support and rigid with the housing 22.The base 24 also acts as an interface for the optic fibres which will bedescribed in more detail below.

Advantageously, the centre-distance of the axes 26 between the twobranches 23A and 23B is adjustable between a minimum distance of 10 mmand a maximum distance of 40 mm.

It should be noted that the centre-distance 26 between the two branchesis adjustable but always fixed during measuring. The depth ofpenetration of the probe may be adjusted between 5 and 15 cm Thediameter of the penetrating branches is about 1 cm.

Advantageously the penetrating ends of the branches are equipped withstainless steel bungs 29.

The length of the branches 23A and 23B is 20 cm.

The branch 23A comprises a window 30A disposed on the inner side of itspenetrating end, perpendicular to the axis of penetration, whereas thebranch 23B comprises a window 30B disposed on the inner side of itspenetrating end, perpendicular to the axis of penetration, and oppositethe window 30A.

Each branch comprises a tube, referenced 25A for branch 23A and 25B forbranch 23B. The tubes are hollow, e.g. made of silica.

The light radiation LE is emitted by a distant light source 40.

The light radiation LE is directed to the non-penetrating end of thebranch 23A by a sheathed optic fibre FOE. In the tube 25A, the lightradiation LE is first guided via an optic fibre 27A and then directedinto a free space up to the window 30A. Finally, the light radiation LEis guided in free space from the window 30A to the piece of meat VI.

The light radiation LE illuminates the meat VI at 90° relative to thelongitudinal axis of penetration of the branch 23A.

The diameter of the emitted light radiation LE is a few mm through thewindow 30A, which is for example made of quartz 1 to 2 mm thick.

A mirror 32A is placed between the outlet of the fibre 27A and thewindow 30A. The mirror 32A is oriented at 45° to the longitudinal axisof penetration of the emission branch 23A in order to reflect at 90° thelight emanating from the optic fibre 27A.

An adapting optic 34A, of the lens type for example, is located betweenthe outlet of the emitting optic fibre 27A and the mirror 30A in orderto adapt the emitted light radiation LE to the volume of meat to beobserved.

The light LT transmitted by the piece of meat VI is received in freespace by the window 30B, disposed perpendicular to the axis ofpenetration of the reception branch 23B.

The diameter of the transmitted light radiation LT is a few mm. Thereception of the light radiation transmitted LT is effected through aquartz window 30B 1 to 2 mm thick.

A mirror 32B is oriented at 45° to the longitudinal axis of penetrationof the reception branch 23B in order to reflect the light transmitted LTtowards a receiving optic fibre 27B disposed parallel to thelongitudinal axis of penetration of the branch 23B.

An adapting optic 34B, of the lens type for example, is provided betweenthe mirror 32B and the inlet of the optic fibre 27B in order to adaptthe light radiation transmitted to the aperture of the optic fibre 27B.

The light transmitted LT is then directed towards measuring means 50 viaa sheathed optic fibre FOR.

Preferably, the measuring means 50 comprise a spectrophotometer SPHequipped with a network (not shown) which disperses the light indifferent wavelengths ranging from the visible to near infrared. Thelight diffracted by the network hits a detection bar such as photodiodeseach capable of recording the light-intensity transmitted in a selectedrange of wavelengths.

For example, the detection bar comprises silicon detectors forwavelengths smaller than 1050 nm and germanium detectors for lengthslarger than 1050 nm.

An amplifying block (not shown) is provided after the detection block inorder to achieve a signal level of between 1 and 10 volts, for example.

As an example, the light source 40 is a tungsten halogen lamp with apower of 20 to 40 Watts. The special features of such a lamp is to beable to emit, within a wide frequency band, a light radiation rangingfor example from the visible spectrum to near infrared.

The probe 23 can be used manually. In this case, it may be separate fromthe light source 40 and the measuring means 50.

Advantageously, the light source and the measuring means are assembledin a common block 52, which is connected to a computer 11.

The optic fibres FOE and FOR have a length of 1 to 2 m in order tominimise attenuation. The diameters of the optic fibres are a few mm.

The emission of the light LE is advantageous interrupted by a rotatingdisc (not shown) located on the optical emission path, rotating forexample at the frequency of 20 to 60 Hertz, in order to permitmeasurements of the signal transmitted in the absence or in the presenceof emitted light.

This timed obstruction makes it possible to overcome variations inexternal light.

It should be noted that the device according to the invention can beformed as a housing comprising a lamp 40 and measuring means 50incorporated in the probe 23 in a single portable housing.

The spectral measurements can also be obtained in reflection mode, withthe application of a probe to the surface or penetration into the meatwhose tenderness is to be determined.

A probe operating by reflection is simpler than a probe operating bytransmission.

For example, with reference to FIG. 5, the probe 100 generally comprisesa single branch 102 for carrying out the outward and return journey ofthe incident light LI and of the reflected light LR.

The branch 102 comprises a single window 104 disposed on the inner sideof its penetrating end, perpendicular to the axis of penetration.

The branch comprises a tube 106, similar to those described withreference to FIG. 4.

The light radiation LI is emitted by a light source. The light radiationLI is directed to the non-penetrating end of the branch 102 by asheathed optic fibre FOER. In the tube 106, the light radiation LI isfirst guided through an optic fibre 114 and then directed in free spaceto a window 104. Finally, the light radiation LI is guided in free spacefrom the window 104 to the piece of meat VI.

The light radiation LI illuminates the meat VI at 90° to thelongitudinal axis of penetration of the branch.

The diameter of the light radiation emitted LI is a few millimetresthrough the window 104, which is for example made of quartz 1 to 2 mmthick.

A mirror 110 is placed between the outlet of the fibre 114 and thewindow 104. The mirror 104 is oriented at 45° to the longitudinal axisof penetration of the branch 102 in order to reflect at 90° the lightemanating from the optic fibre 114.

An adaptation optic 112, of the lens type for example, is placed betweenthe outlet of the optic fibre 114 and the mirror 110 in order to adaptthe light radiation emitted LI to the volume of meat to be observed.

The light reflected LR by the piece of meat VI is received in free spaceby the window 104 and crosses the branch in the opposite direction tothat of propagation of incident light LI. The reflected light LR is thendirected towards the measuring means by the emission/reception opticfibre FOER.

Like the probe described with reference to FIGS. 3 and 4, the probe 100is connected to a light source and a spectrophotometer which may besimilar to those described with reference to FIGS. 3 and 4. In practice,the source and the spectrophotometer are combined in a common blockconnected to the probe via a single optic fibre FOER for carrying theincident light as well as for carrying the reflected light.

The light source may comprise upstream a monochromator, whose dispersiveprinciple permits scanning of the spectral field from 400 to 2500 nm.

Determination according to the invention is objective, non-destructive,and is set up on the transformation site in an industrial environmentwithout having recourse to sophisticated, expensive devices. In general,the reliability is improved when numerous spectral data DSP andnon-spectral data DAC are integrated in the determination model However,some parameters (1 to 5 for example) of the DAC type (which may varyfrom one determination model to another according to the piece of meatbeing analysed, the animal, and the homogeneity of the population) inassociation with spectral data DSP may suffice to achieve satisfactoryreliability.

What is claimed is:
 1. A method of determining the quality of meat in atransformation site, comprising: a) collecting, on the transformationsite, data relating to parameters belonging to the group consisting ofbreed, age and category of animal and biological and/or physico-chemicalparameters of the animal carcass belonging to the group consisting ofweight, conformation, fleshing, pH value, colour of the carcass, andthickness of the hide, b) obtaining at least one optical spectrum of themeat corresponding to wavelengths belonging to a spectral field rangingfrom visible light to near infrared, and c) combining the data obtainedduring steps a) and b) with a view to determining the tenderness of themeat according to a predetermined equation relative to a predeterminedscale of reference of tenderness.
 2. The method according to claim 1,wherein step b) is carried out in reflection and/or transmission mode.3. The method according to claim 2, wherein step b) comprises: b1)providing a probe comprising an emission branch and a reception branch,spaced apart by a predetermined distance; b2) inserting the emission andreception branches into a selected piece of meat to a selected depth;b3) illuminating the piece of meat by means of the emission branch thusinserted into the piece of meat by wide-band light radiation at afrequency ranging from visible light to near infrared; b4) receiving thelight transmitted by the piece of meat by means of the receiving branchthus inserted into the piece of meat; and b5) recording a transmissionspectrum of the piece of meat ranging from visible light to at leastnear infrared.
 4. The method according to claim 1, wherein the equationof determination is drawn up over a series of different pieces of meatof different animals for each of which spectral data and non-spectraldata are obtained according to steps a) and b) and compared to a scaleof reference drawn up by means of sensorial data and/or data of theshearing force, and/or of the force of compression measured over thesignificant series of different pieces of meat.
 5. The method accordingto claim 1, wherein the equation of determination is carried out by amultidimensional statistical method in order to obtain a mathematicaldetermination model intended to be used on each piece of meat whosetenderness is to be determined.
 6. The method according to claim 1,wherein spectral variables are processed according to an analysis of amain component of a similar process.
 7. The method according to claim 1,wherein step b) is carried out on a carcass, quarter, muscle or steak.8. The method of claim 1, wherein the meat is beef.
 9. The method ofclaim 5, wherein the multidimensional statistical method comprises themethod of the smallest partial squares.
 10. A device for determining thequality of meat on a transformation site, comprising: means ofcollecting on the transformation site, data relating to parametersbelonging to the group consisting of breed, age and category of animaland biological and/or physico-chemical parameters of the animal carcassbelonging to the group consisting of weight, conformation, fleshing, pHvalue, colour of the carcass, and thickness of the hide, means ofobtaining at least one optical spectrum of the meat corresponding towavelengths belonging to a spectral field ranging from visible light tonear infrared, and processing means for combining the data obtained fromthe means of collecting and means of obtaining with a view todetermining the tenderness of the meat according to a predeterminedequation relative to a predetermined scale of reference of tenderness.11. The device according to claim 10, wherein the means of obtaining aspectrum comprises: a probe comprising an emission branch and areception branch, spaced apart a predetermined distance and capable ofbeing inserted into a selected piece of meat to a selected depth; alight source capable of sending a wide-band light radiation at afrequency ranging from visible light to near infrared, and opticallyconnected to the emission branch in order to illuminate the piece ofmeat by means of the emission branch thus inserted into the piece ofmeat; and measuring means capable of recording a transmission spectrumof the piece of meat ranging from the visible to near infrared andoptically connected to the reception branch in order to measure theintensity of the light transmitted by the piece of meat and received bythe reception branch thus inserted into the piece of meat.
 12. Thedevice according to claim 11, wherein the emission branch comprises awindow disposed perpendicular to the longitudinal axis of penetration ofthe emission branch and at least one emitting optic fibre opticallyconnecting the light source to the window of the first branch.
 13. Thedevice according to claim 11, wherein the reception branch comprises awindow disposed perpendicular to the longitudinal axis or penetration ofthe reception branch, opposite the window of the emission branch, and atleast one receiving optic fibre optically connecting the window of thesecond branch to the measuring means.
 14. The device according to claim11, wherein the the two branches is adjustable in order to carry outoptical measurements in a volume of meat of a few cm³.
 15. The deviceaccording to claim 10, wherein the means of obtaining a spectrumcomprises: a probe comprising an emission/reception branch capable ofbeing inserted into a selected piece of meat to a selected depth; alight source capable of sending a wide-band light radiation at afrequency ranging from the visible to near infrared, and opticallyconnected to the emission/reception branch in order to illuminate thepiece of meat by means of the emission/reception branch thus insertedinto the piece of meat; and measuring means capable of recording areflection spectrum of the piece of meat ranging from the visible tonear infrared and optically connected to the emission/reception branchin order to measure the intensity of the light reflected by the piece ofmeat and received by the emission/reception branch thus inserted intothe piece of meat.